Continuous-track tractor



Patented June 13, 1939 I PATENT OFFICE commons-macs 'rnsc'roa Arthur W. errington,

Indianapolis, ma, as-

signor to Mailman-Remington ('Jonnmamr, Inc., Indianapolis, Ind, a corporation of Indiana Application March as, an, Serial No. 132,900

2 one.

The object of my invention is to provide an improved resilient pivotal mounting for the idler road supporting wheels for an endless-track, or track-laying type of motor vehicles.

The accompanying drawing illustrates my invention: 1

Fig. l is a diagrammatic fragmentary side elevation outline of a vehicle embodying my inven tion;

Fig. 2 is a side elevation, in partial vertical section, on a larger scale, of one pair of load-supporting idlers, and associated traclr fragment, constructed in accordance with myinvention;

Fig. 3 is a section on line i i-i! of Fig. 2 but on ya larger scale; and

Fig. 4.- is a fragmentary section on line il-t of Fig. 2 showing a slight modification.

In the drawing it indicates the main body of the vehicle having the usual traclr driving sprochet i I, track supporting idler i2 and endless traeit belt it of usual form.'

Secured to each side of the main body it are brackets it, each carrying a fixed horizontal trunnion pin it carrying two bearing bushings it. it upon which are journaled thimbles or shells ll, ll within which ar non-rotatively mounted metal rings it, It to the inner surfaces of which are vulcanized the external surfaces of rubber rings it, It the inner surfaces of which are vulcanized to the external surface of a metal ring 20, the bore of which is conveniently somewhat larger than the external diameters of the hub portion ll of shells ll.

To each shell H is secured a radially projecting arm 2! provided at its outer end with a bearing sleeve 22 in which is journaled an idler wheel structure 23 which rests upon the lower run of the track belt l3. Each shell ll also carries an upwardly projectingarm M which carries a resilient bumper 25.

The two elements l9, [9 may be a single continuous element (without the intermediate notch l9).

The two shells IT, I! are initially non-rotatively associated with the tubes I 8, H3 at an angular relationship approximately as indicated by dotted lines in Fig. 2 so that, when the unit illustrated in Figs. 2 and 3 is placed in position on trunnion pin 15 the two idler carrying arms 2i, 2! must be swung upwardly. so as to oppositely torsionally circumferentially stress the rubber ring l9, I9. a

The initial torsion stressing of the rubber l9, l9

' provides a downward bias for each idler and the torsional elastic limit of the rubber I9, I9 is with a cup-shaped pivoting element, a-connectsuch as to permit necessary upward yield oi each idler, the force (due to the passage. of the trash over a local ground elevation) causing such upward yield being transmitted through the rubber it, it and inner ring it to the companion idler through its carrying arm ii.

The necessary diameter and radial thickness of the rubber id will, of course, be dependent upon the load conditions and quality of the rubber, all oi which may be readily determined for a 3) given road condition by methods of computation well known.

The bumper elements iii face each other and limit relative spreading of the companion idler carrying arms it, it.

It will be readily understood that in some instances the rubber. sections it, it need not be completely annular but that the probabilities are that complete annuli will be more satisfactory from production and operative viewpoints.

It will be noted that the hubs ll! of shell ii are oppositely shouldered against'their respective bushings it which are held against axial movement outwardly by the arms of bracket it so that the idler wheel unit, comprising the two M associated idlers and their carrying arms, is held against movement axially of pin l5 so that the rubber torsion element It is not subjected to stresses axially thereof.

This is quite important tor the reason that, if the inner periphery of the rubber torsionelement were vulcanized directly to the pivot pin- !5, the idler wheel unit would be subjected to stresses'axially of the pivotal mounting thus aifording a possibility of lateral wobble of the main body of the vehicle. j I

In Fig. 4, I show a" slight modification wherein the inner ends of the hub portions l'l' abut upon opposite sides of a thrust ring 60 mounted upon pin it.

I claim as my invention: a

1. In a vehicle of the track-laying type, a loadsupporting idler group, comprising a pair of coaxial swinging idler-carrying arms, each provided ing unit sleeved within said-pair of cup-shaped elements and non-rotatively associated with each of said cup-shaped elements without substantial compression, said connectingunit comprising cirqumferentially yieldable rubber portions which are respectively non-rotatively anchored to said cups and to each other, and means limiting the relative movement of the two arms within the elastic and bonded limits'of said rubber portions.

2. In a vehicle of the track-laying type, a load- 55 supporting idler group, comprising a pair 0! coaxial swinging idler-carrying arms, each provided with a cup-shaped pivoting element, and a connecting unit sleeved within said pair 01' cupshaped elements, said units comprising a central sleeve, two 'axially spaced rubber annuli adherent with the respective cup-shaped elements.

ARTHUR W. HERRHIGTON. 

